Nowadays, scanners have become basic equipments of most computer's users. Both texts and pictures can be placed on scanners to be faithfully read in. The principle of scanner is very simple. Part of a document (manuscript) is illuminated by light, and the reflected light is read to obtain the image of this part. Additionally, the scanned image can be read in an image processing software for adjustment. If the scanned one is a printed matter, an optical character recognition (OCR) software can also be used to convert the printed matter into a text stored in a computer.
As shown in FIG. 1, a sensor 10a (e.g., a charge-coupled device (CCD) or a contact image sensor (CIS)) is disposed inside a prior art scanner. An axle sleeve 11a and a belt clamping seat 12a are disposed at the bottom of the sensor 10a. The axle sleeve 11a is sleeved onto and matched with a guide rod 13a. The belt clamping seat 12a can be clamped on a belt 14a, which uses a motor (not shown) as the power source. A gear set (not shown) disposed inside the scanner is used for transmitting power of the motor to the belt 14a so that the sensor 10a can be driven by the belt 14a to move on the guide rod 13a. The sensor 10a can thus move along the scanning direction to perform the scanning action.
However, the gear set of the above prior art image read module occupies much space, and uses many components, resulting in complicated assembly, high cost, and large size of the scanner and thus not conforming to the compactness requirement of present products.
Accordingly, the above image read module has drawbacks and inconvenience in practical use. The present invention aims to resolve the problems in the prior art.